fix(mcp-server): review fixes for the draw.io file list and its guard

- The list now ships the templates of Insert > Template, the PlantUML
  parser of Insert > Advanced and the template dialog's icon: the menu
  items were shown but failed with 404s. 15.1 MB packed; the tarball cap
  goes from 40 MB to 20 MB, where it still catches a list that grew by a
  whole js/ directory.
- The guard drives both features, fails when the copy it runs against
  lacks files the editor asked for or when an export does not answer,
  checks that the copy is the pinned draw.io version, and runs in CI
  (npm run check-drawio, one E2E shard) so a list regression cannot reach
  a release.

.github/workflows/test.yml

@@ -81,6 +81,13 @@ jobs:
       - name: Build app
         run: npm run build
 
+      # The MCP package ships a trimmed draw.io; this drives the full copy
+      # (public/drawio, downloaded by the build) in Chromium and fails when
+      # the editor requests a file its list does not have. Once is enough.
+      - name: Check the MCP draw.io file list
+        if: matrix.shard == 1
+        run: npm --prefix packages/mcp-server run check-drawio
+
       - name: Run E2E tests
         run: npm run test:e2e -- --shard=${{ matrix.shard }}/6
         env: